- 


Circular  \ 


United  States  Department  of  Agriculture^ 

MUKLAg   OF    ENTOMOLOGY, 
t    .>   how  a  ii  ran. 


i;i:  \  I* in  N<  ILE. 
ui<ii>.  i 

Sami 

From  even  State  nasi  <>!'  the  Mississippi  Uiver,  and  from  Missouri, 
Arkansas,  Louisiana,  Tex 
as,  Minnesota,  and  the 
Province  <>t'  <  mtario, 
ada,  the  terrapin  scale  has 
been  reported  and  authen- 
tic specimens  have  been 
received  by  ilii-  Office.  It 
i*.  noteworthy  that  this  spe- 
cies of  scale,  more  conspic- 
nously  marked  than  any 
other  of  the  genus,  is  the 
most  generally  injurious 
one.  In  consequence  <>t"  ii- 
wide  range  of  food  plants. 
including  both  wild  and 
cultivated  trees,  it  must  be 
considered  a  dangerous 
pest,  which  may  be  con 
trolled  but  never  eradi- 
cated. 

This  scale  insect  can  be 
rnized  and  identified 
especially  well  i'i  the  hiber- 
nating u  inter  stage  i fig.  I). 
when  it  appears  as  ;i  red- 
dish hemispherical  scale  2 
nun.  in  length,  mottled 
with  radiating  streaks  of 
black  w  hich  are  especially 
conspicuous  about  the  mar- 
gin. Sometimes  these  radi 
ating  streaks  coalesce, 
forming's  subdorsal  dark  Imnd  surrounding  the  central  reddish  boss, 
isionally  individuals  are  founSi  which  are  entirely  red  or  black. 


Although  this  species  was  not  described  until  1898,°  the  describer, 
Mr.  Theodore  Pergande,  of  this  Office,  hud  known  it  since  1872,  when 
it  was  found  upon  peach  trees  at  Hillsboro,  Mo. 

FOOD    PLANTS. 

For  many  years  the  terrapin  scale  has  been  considered  a  specific 
enemy  of  the  peach  and  lias  been  confounded  by  many  entomologists 
and  others  with  Eylecanium  persicae  (Fab.),  the  preeminent  peach  soft 
scale  of  Europe.  At  present  we  know  it  as  infesting  a  large  number 
of  host  plants,  including  many  varieties  of  peach  and  cultivated  plum; 
various  species  of  wild  plums  and  cherries;  Prunus  simonii,  apple; 
pear;  quince;  several  species  of  Crataegus;  three  species  of  maple,  par- 
ticularly Acer  saccharinum;  oriental  and  western  sycamores;  Carolina 
poplar;  olive;  blueberry  (Vhccmium  -p.):  Bumelia,  and  spice  bush 
{Benzoin  benzoin ). 

DESCRIPTION. 

The  following  technical  description  is  inserted  to  facilitate  the  deter- 
mination of  this  species  by  entomologists,  or  anyone  who  may  have 
access  to  a  compound  microscope. 

Adult  female  (fig.  2) . — Nearly  hemispherical,  small.  Length  .">  to  3.5  mm.,  exhibiting 
many  of  the  superficial  characters  of  the  hibernating  form  described  above,  though 
showing  a  tendency  to  fade  rapidly  after  oviposition  until  by  the 
autumn  she  is  plain  dull  yellow  or  terra-cotta  color.  Fresh 
unrubbed  specimens  are  covered  by  a  thin  glassy  secretion  of  wax 
which  scales  off  readily.  When  cleared  by  boiling  in  a  solution 
of  potassium  hydroxid,  the  derm  is  left  quite  colorless,  excepting 
the  brown  chitinized  anal  lobes  and  a  narrow  chitinized  area 
surrounding  the  lobes.  Antenna-  (iig.  3,  b)  composed  of  six 
segments;  segment,;!  which,  occasionally  shows  a  pseudo-joint,  is 
FlG'  ,2-~Tfrra?in     equal  in  length  to  4.  5,  and  6  together;  next  in  order  of  length 

scalf   I  Lull  mil i u in  l  "  c  ,        .  '     . 

nigrofasciatum  \:      come  segments  2  and  1  m  order.      The  antenna'  exhibit  the  ordi- 

Adult   female,      nary  cheetotaxy.     Legs  well  developed:  tibia  slightly  longer  than 

Enlarged  (after     tarsus,  bearing  a  pair  of  Long,  knobbed  tarsal  digitules  and  a  pair 

of  long  expanded  ungual  digitules.     There  are  irregular  rows  of 

many  pores  leading  from  the  spiracles  to  the  spiracular  spines  (fig.  3,  c)  on  the 

margin  of  the  body.     The  median  spiracular  spine  of  each  group  is  robust  and  about 

50  mm.  long,  three  times  the  length  of  the  two  shorter  spines;  marginal  sp 

(fig.  3,  d)    slender,  about  equidistant,  except  four,  which  are  closely  crowded  at  the 

anterior  median  point. 

The  distinguishing  microscopical  characteristic  i  if  this  species  is  the  irregular  single 
or  double  mid-dorsal  row  of  25  to  40  low,  subcorneal  appendages  i  fig.  3,  -  ),  appearing 
like  pores,  extending  from  near  the  anal  lobes  to  nearly  above  the  sucking  mouth- 
parts.  These  pores  are  usually  quite  evident  in  a  mounted  specimen  and  serve  to 
separate  this  species  surely  from  all  others.  The  thick  anal  plates  (fig.  .">.  a)  are 
quite  symmetrical,  somewhat  longer  than  broad,  with  the  posterior  lateral  margin 
rounded  and  thickened.     Each   plate  bears  two  minute  apical  and  two  subapical 


«Bul.  18,  n.  s.,  Div.  F.nt.,  V.  S.  Dept.  Agric,  pp.  26-29. 

[Cir.88] 


8 

loiigei   --I  ■ii' 
ih ter  ■ 

Tin'  in. ill-  "i  tin-  -|"  i  hiili 

1-1  i.      I'll,  ii!  H-vnt  wings  have  an  <  nit  4  mm. 

ii -I.  with  - lark  n  icic  band, 

This  species  should   riul   be  confounded  with  /  m  priin 

I  onMc),  :i  small,  \<t\  convex,  dark  red,  shining  species,  which  has  ;i 
group  of  mam  (200  to  3<  H))  pores  with  interspersed  spines,  extending 
from  the  anal  lobes  i«>  mar  the  anterior  margin;  the  spiracular  spines 
are  nearh  uniform  in  length,  being  scarcely  longer  than  i h«-  marginal 
spines.  The  latter  specie**  «:i-  first  recorded  from  the  United  States 
in  November,  1894,  when  il  wassenl  to  this  Office  from  Columbia,  Pa., 
<ui  plum  twigs.  Europe  is  it-  original  borne,  whence  it  must  have 
been  exported  to  the  lTnited  States  on  nursen  stock  or  cuttings. 


I 

r  \i;  \-i  ii-. 

Very  small,  parasitic  four-winged  flies  of  the  genus  Coccophagus, 
family  Chalcidicbe,  are  our  greatesl  benefactors  in  the  control  of  thi- 
scale  insect. 

i;imi  I'll  B. 

Unfortunately  1 1 1 » •  lime-sulphur  wash,  which  i-  such  an  excellent 
remedy  for  the  San  Jose  scale  and  which  at  the  same  time  controls  the 
peach  leaf -curl,  is  worthless  for  treating  the  terrapin  scale.  Numerous 
experiments  in  the  use  of  the  lime-sulphur  wash  against  this  scale  on 
various  host  plant-  have  produced  only  negative  results. 


JL 

4  3  1262  09216  4473 

Kerosene  emulsion  has  proved  to  be  the  most  effective  remedy  for 

the  control  of  this  pest.  This  emulsion,  when  properly  made  accord- 
ing to  the  formula  below,  can  be  sprayed  with  safety  on  any  tree  dur- 
ing the  dormant  period— in  winter  or  early  spring  lie  fore  the  buds 
(lpen  at  a  strength  of  20  to  25  percent.  A  nozzle  throwing  a  fine 
spray  should  he  used.  Care  should  always  he  exercised  to  prevent  the 
liquid  from  running  down  the  trunk  of  the  tree  and  collecting  ahout 
the  root-,  as  the  oil.  which  will  lie  retained  by  the  soil  around  the  root- 
for  an  indefinite  period,  might  seriously  injure  or  kill  the  tree. 

KEROSENE    EMULSION. 

stork  solution  (66  per  cent  "il). 

Kerosene  i  coal-oil,  lamp-oil  I gallons..  2 

Whale-oil  or  laundry  Boap    »rl  quart  soft  soap  i pound.,   J 

Water gallon..   I 

Dissolve  the  soap  in  boiling  water,  fin  ,<  remove  from  thefre,  add  the 
kerosene  immediately  and  thoroughly  agitate  the  mixture  until  a  creamy 
solution  is  obtained.  This  can  be  done  by  pouring  the  mixture  into 
the  tank  of  a  spray-pump  and  pumping  the  liquid  through  the  nozzle 
back  into  the  tank.  This  i-  a  stock  solution  which  must  be  diluted 
before  using.  In  order  to  make  a  20  per  cent  emulsion,  add  to  each 
gallon  <»f  the  stock  solution  about  2i  gallons  of  water  and  agitate  thor- 
oughly before  using.  For  a  25  per  cent  solution  add  to  each  gallon  of 
the  stock  solution  1|  gallons  of  water  and  agitate  thoroughly.  This 
strength  will  kill  a  large  percentage  of  the  hibernating  female-,  with- 
out injury  to  the  tree-. 

If  a  good  naphtha  soapcan  be  obtained  the  preparation  of  the  emul- 
sion will  be  simplified.  It  will  be  unnecessary  to  heat  the  solution, 
Since  the  kerosene  will  combine  readily  with  the  naphtha  and  soap  and 
form  a  perfect,  cold,  milky-white  emulsion  when  the  mixture  is  thor- 
oughly agitated.  If  naphtha  soap  is  used,  double  the  amount  called 
for  by  the  formula,  and  emulsify  in  soft  (rain I  water. 

Approved: 

James  Wilson, 

Secretary  of  Agriculture. 
Washington,  D.  C,  Aprils,  1907. 

Cii   -'- 

O 


